LTCC (Low Temperature Cofired Ceramic) technology makes it possible to realize ceramic multilayer components with several metallization levels, into which a plurality of passive components such as conductor traces, resistors, capacitors and inductors can be integrated. Thus, circuits and components comprising these circuits can be realized in LTCC ceramic substrates.
The greater the dielectric constant of the ceramic material that is used in LTCC technology, the higher an integration of capacitors is possible. On the other hand, an excessively high dielectric constant is disadvantageous for the integration of the inductors, so that the ceramic selection must be optimized with regard to its dielectric constant. Further requirements of the ceramic material are a sufficiently low sintering temperature to enable the use of economical electrode materials such as silver. In addition, the ceramic material should have only a slight temperature variance of its dielectric and other properties so that the component produced with LTCC technology can be used in a wide temperature interval without its properties changing excessively.
So far it has not been possible to find a ceramic material having a dielectric constant above twenty with a sufficiently low sintering temperature, or whose dielectric constants have the necessary temperature stability and which can be processed with LTCC technology.